Notes: The adverb for this good adjective is perspicaciously and the noun indicating that special capacity of perspicacious people is perspicacity [pêr-spê-'kæ-si-ti]. Perspicacious implies an ability to perceive hidden truths that others fail to see. Perceptive, as you see, has a more general sense, to be able to see anything clearly. A sagacious person has a cumulative wisdom that grows over a long period of time.

In Play: This is a word that should be part of our lexical arsenal for distinguishing different kinds of intelligence. "She isn't particularly sagacious, but she was perspicacious enough to dump Phil Anders when he started asking her to trust him." It is a good lexical tool for work, too: "Clair Voyant is so perspicacious she can predict future market trends from changes in the menus at MacDonald's."

Word History: Today's Good Word comes to us from Latin perspicere "to look through" from per "through" + spicere "see, look". It is in obvious ways akin to perspective. The PIE root underlying spicere, *spek-, lost its tail making its way to English spy. In Greek, it metathesized (the consonants switched places), becoming skop- "see", the root which underlies our words telescope, microscope, periscope. (Thanks to Grogie of the Alpha Agora, who had the perspicacity to spot perspicacious and recommend it to the gremlins who decide which words are good and which, not.)